And people with health conditions including heart problems and asthma have been warned to take care and stay indoors as temperatures plummet.

Campaigners fear this winter could even bring "unprecedented numbers" of deaths amid forecasts of severe cold weather into mid-March.

Malcolm Booth, chief executive of the National Federation of Occupational Pensioners, said: "Last year's excess winter death figures were pretty horrendous even though it was a relatively mild year.

"With a cold spell like this the risk is this number will rise if people, especially the elderly, do not take great care. We could be facing unprecedented numbers this year."

Last year saw 34,300 excess winter deaths in England and Wales caused by slips, falls and illness, according to the Office for National Statistics.

In the winter of 2014-15 there were 43,900 deaths, the highest number since 1999-2000 when there were 48,400.

Latest PHE figures reveal there have been 150 new admissions to intensive care units with influenza since mid-February.

More than 750 people were reported as being in hospital with the flu, including the deadly Australian strain, last week.

Dr Richard Pebody, PHE's acting head of respiratory diseases, said: "We have seen significantly more deaths than we'd usually expect to see this winter, particularly in over-65s in England.

"The very cold weather some areas have seen since Christmas and the strains of flu circulating this winter are likely to be important contributing factors.

"These both tend to affect the elderly and those with underlying conditions."

Charities have warned people with health problems to take extra care over the next few weeks.

Caroline Abrahams, charity director for Age UK, added: "Simple precautions such as wrapping up warm when going outside, sleeping with the windows closed at night and having plenty of hot food and drinks throughout the day can help keep these risks at bay."